Assisted Hatching (AH) of Embryos

In Vitro Fertilization Program

Embryos and/or patients that meet the criteria below are candidates for selective assisted hatching.  Good quality embryos demonstrating a normal rate of development will not receive the assisted hatching treatment as it may reduce a good quality embryo’s ability to implant into the uterus.  Assisted hatching is performed on cleavage-stage embryos that are transferred to the uterus three days after egg retrieval.  The UI Hospitals and Clinics IVF laboratory does not perform assisted hatching on blastocysts (embryo transfer five days after egg retrieval).

Assisted hatching has been shown to improve embryonic implantation rates in women who:

• have failed to achieve embryonic implantation after several IVF cycles
• have poor quality embryos or embryos that are behind in development

A soft shell called the zona pellucida surrounds the embryo.  The zona pellucida protects the embryo during early development.  As the embryo develops, the zona pellucida thins.  The embryo must hatch out of the zona pellucida prior to implantation into the uterine wall.  It has been suggested that some unsuccessful cycles of assisted reproduction are due to the inability of the embryo to hatch out of the zona pellucida or delayed hatching which prevents the embryo from subsequently implanting into the uterine wall during the implantation “window of opportunity”.

Embryos that may otherwise remain trapped within the zona pellucida may be rescued by a technique called assisted hatching.  Assisted hatching at the UI Hospitals and Clinics IVF laboratory is accomplished by dissolving a small hole in the zona pellucida just prior to transcervical embryo transfer.  It is through this small hole that the embryo may eventually hatch out of a zona pellucida.